The common nail has a round smooth shank.

A spiral nail has a continuously twisted shank, so that the nail rotates when it is nailed into a board which makes it grip significantly better than a common nail. In effect, a spiral nail acts like a screw.

The nail is ubiquitous with allowing us to build exacting shelters and has effectively civilized us into the modern era, which — like potable running water — we take for granted these days.

A better shelter is more efficient, appropriately sized, and faster to build.  Remember, that prepping and bugging-out is all about efficiency.

What you are doing is stock piling “energy” for later use.

In the case of nails, you are minimizing your future efforts — that is, minimizing your energy usage and time expenditure when it comes to making the second most important survival component (shelter), after water (think of the order or sequence of the survival rules-of-3).

You want to pack a small bunch of 3.5″ (16d) or 4″ (20d) galvanized spiral nails.

These are readily available at any hardware store and are now the de facto-standard in the construction industry, used primarily for framing houses.

Although a nail is made out of hardened steel, it can be bent into an eye hook shape, especially if you carry some pliers.

For a trivial additional cost, hot-dipped galvanized nails will prevent the nail from rusting.

The preferred 4″ nail length can effectively and strongly put together dimensional lumber — like 2×4’s.

Also, 4″ is sufficiently long enough to nail into a board or tree, leaving about 2″ sticking out as a makeshift hook, and still have enough strength to hold up something substantial or act as an anchor to tie things to.

Also, if you need to pull the nail out to re-use it, at least you’ll have something you can grip on to.

A handful of nails in your bug-out bag will go a long way.

Canadian Prepper has an excellent video discussing additional uses for nails.